With all of the free games both brands are giving away, you would be surprised how much extra they are getting that Nintendo barely has ever scratched the surface on providing (outside of a competent gaming OS).

Wii U so you can play other games!

Wii U, though that price is not a deal, it's the regular price
Still a better purchase

If you already have a PS4, I see no reason to buy a XboxOne, since many of its great games are multiplatform and can be played on PC, with very few exceptions.
Go for the WiiU, you´ll save money that can be used to buy bunches of exclusive games. Plus, the WiiU in the future will be a rare collector´s piece and it´s perfect for gaming parties.

I would say neither and I own both consoles....

So it's only "no reason" if someone has a PS4 and a potent PC.